Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Other comprehensive income, net of tax
Unrealized net holding (losses) gains arising during the period, pre-tax amounts	$ 1,463	$ 5,978	$ 1,798	$ 13,719
Reclassification adjustment for net gains related to securities available for sale included in net income, pre-tax amounts	26	12	578	98
Amortization of prior service cost and actuarial gains, pre-tax amounts	$ 989	$ 417	$ 2,702	$ 1,248